Liquid level indicating device



July 25, 195o C. A. DE GIERS El' AL LIQUID LEVEL INDICATING DEVICE 4 Sheets-Sheet 1 Filed March 27, 1946 IN1/EN rozas CZAREA/GE/l. DE G/EHS OU/.s M CAMP/4 /v/ A TTQRNEY July 25, 1950 c. A. DE GlERs Er AL LIQUID LEVEL INDICATING DEVICE y4 Sheets-Sheet 2 Filed March 27, 1946 I N V EN T0 RS OARE/VCEADEG/ERS ws M OAMFAN/ l TTORZE'Y July 25, 1950 c. A. DE GlERs Er Al. 2,516,452

LIQUID LEVEL INDICATING DEVICE Filed March 27, 1946 4 Sheets-Sheet 3 Q! soo 550 AIN FUEL U5 GAL EAD READ n DIALZ a E l N VEN T RS ZAM-N05 4. .DE /ERS L 4oms M CAMP/1 /v/ BY M@ ATTORAEY July 25, 1950 c. A. DE GlERs Er AL LIQUID LEVEL INDICAIING DEVICE 4 Sheets-Sheet 4 Filed March 27, 1946 1N Ares/vos @FEU DON wir@ owe mix@ ooh w15@ oo@ V NTORS CL DE 67E/Es ou/5 M OAMPAN/ ATTORNEY patented .uy 25, Q

LIQUID LEVEL INDICATING DEVICE Clarence A. de Giers, Forest Hills, and Louis M. Campani, Freeport, N. Y., assignors to The Liquidometer Corporation, Long Island City, N. Y., a corporation of Delaware Application March 2'7, 1946, Serial N o. 657,393

1 Claim.

This invention relates to electrical indicating and telemetric systems, and particularly to the measurement of a fluid in a container or tank.

One of the objects of the invention is to provide an electrical system and a combination of instrumentalities for measuring the contents oi fuel tanks, either stationary or for aircraft, whereby the effective scale length of the indicator is multiplied several times Without enlargement of the space required by the indicator.

Another object of the invention is to improve the accuracy, and increase the readability of the measuring system.

A further object of the invention is to provide, for a given tank, a number of transmitting elements which are independent of each other to the extent that a failure in any one of them will not aiiect the performance or accuracy of other parts o1' the complete system, but merely of the element affected.

A further object of the invention is to provide means whereby the errors due to the tilting of ya tank, such as when used for aircraft can be substantially reduced.

A further object of the invention is to provide a system which is simple to maintain and install.

In present day aircraft, the panel space is very limited due to the multiplicity of instruments required for its operation. Hence the size and scale length of each indicator is necessarily limited, reducing the readability and accuracy of the system. This condition is further aggravated by the increase in size of fuel tanks of modern planes which require that much' larger capacities be indicated on existing indicator thus causing the scale calibration to become even more crowded. A further limitation of existing systems is that a failure in the transmitter will usually render the Whole system useless. vIn aircraft this is a serious condition since the pilot will not be able to know the amount of gas which he has lelt to continue his flight.

In a preferred form of the invention, it is proposed to use an indicator cooperating with a number of float operated transmitter elements.

The indicator is equipped with a number of dials, only one of which appears on the face of the indicator at a given time. The dials are selected by a suitable mechanism controlled by a knob on the face of the instrument. This knob simultaneously operates an electrical selector switch connecting to the various transmitting elements in the system. The transmitting elements are suitably located at different levels in the tankto be 2 gauged so that each float covers a total vertical height of the tank.

Since each transmitter is made to indicate on a separate dial, the eifective scale length is multiplied by the number 0i' transmitter elements used without increasing the size of the receiver. Also, since each transmitter is mechanically and electrically separate from all the others, failure in any one will only disrupt the loperation of the system over its range leaving all vothers to operate at their original accuracy.

Other and further objects of this invention portion of the vwill be more apparent after an examination of the specification inconjunction with the accompanying drawings. It is understood, however, that the drawings are for purpose of illustration only and are not intended to define the limits of the invention.

In the drawings:

Fig. l illustrates schematically-an arrangement of the invention, the liquid level shown not being related to the position of the indicator, which is shown diagrammatically only for clearness of illustration;

Fig. 2 is a side view of a typical indicator used in conjunction with the invention;

Fig. 3 shows the indicator ofI Fig. 2 with parts cut away to expose some of the indicator operating mechanism to view;

Fig. e is a front view of one of the indicators employed;

Figs. 5 and 6 are respectively, sections along the lines 5--5 and 6 6 of Fig. 3;`

Fig. 7 is a section along the line 'l-l of Fig. 6;

Fig. 8 indicates diagrammatically a comparison of effective scale'length made possible by the invention; and

Fig. 9 illustrates a system embodying the invention in which the transmitters are allowed to overlap through certain portions ofr their travel.

Fig. 1 illustrates schematically the basic principle of the invention. `Tank Il holds the uid to be measured by indicator l2. By way of illustration, three oat operated transmitters I3, I4 and I5 are so arranged in said tank that 'transmitter i3 will cover the lower portion of the tank up to level I6, transmitter I4 will cover the center portion of the tank, such as from level I6 to level I8 and transmitter l5 will cover the upper portion of the tank such as from level I8 to level i9.

Transmitters i3, I4 and IE are of the conventional type, and in lthemselves are not novel. Referring to Fig. 1, transmitter i3 may be composed assieme tents the scale length of two typicalF dials in an indicator such as I2 when .placed end for end and arranged to cover a 300 degree span; scale 38 is more than twice as longas that found in a typical indicator having a 300 degreescale as indicated by scale 36. Since the scale has been made longer, it follows that the readability of the instrument is proportionally increased. Y

In the adjustment of the transmitters, it was indicated that each transmitter was adjusted at the normal top and bottomv of its travel. where the conventional transmitter can be adjusted to read exactly 'at two points, Empty and Full the arrangement used in the present invention can be adjusted to read exactly at a number of intermediate levels such as at 200 and 400 gallons. This improves the accuracy at other levels. It will also become apparent from the description of the circuit arrangement, that sincev each transmitter is independent from all others, a failure in any one of them will not aiect the readings of the others. Hence, assuming that the upper transmitter fails, the upper range under the supervision of transmitter l5, Fig. 1 will not be usable, but the two lower positions will still be operative and usable at their original `accuracy. Hence while the operator is inconvenienced by not knowing what his upper level is, he will still be able to use the remaining'sections of his system and not lose the complete use described in greater detail. By way of example, -f r Fig. 9 illustrates a' tank equipped with 'three transmitters 42, 43 and 49 which are similar to |3, I4 and l5, Fig. l, but in this case are made to overlap to a large extent in the amount of iluid spanned by each transmitter. Here again, the wiring has been conventionally indicated, but can be assumed to be entirely similar to that shown in Fig. l. Transmitter 42 is made to cover the levels from Empty to 300 gallons. Transmitter 43 is made to operate from the 150 gal- 1 lon level to the "45|l gallon level, thus overlapping transmitter 42 from the 150 to the "300 gallon level. Transmitter 49 is made to operate from the 300 gallon level to the 600 gallon level, and thus `overlaps transmitter 43 from the 300 to 450 gallon levels. Cooperating with the transmitters is indicator |2b having in position 1 a dial 2lb calibrated from E to 300, gallons. `In position 2 is dial 22b`calibrated from "150 to 450 gallons. In position 3 is a dial 23h calibrated from 300 to 600 gallons.

In operation, as the fuel rises from Empty to 300 gallons, the pointer 20d will swing from E" to 300 if the selector switch of indicator I2?) is set to position when the fuel level rises above the 300 gallon level, the pointer will swing above .the 300 mark indicating that the indicator should be set to position 2. If desired the section between "150 and 300 marks may be suitably identied as overlap sections so that the-op- Hence switched to position 3, 'on dial 22h.

vreading may be 375.

erator may lknow that he can switch vto the next vhigher'position 'at any time when thepointer is in the overlap zone.' A similar procedure is fol-- lowed for all otherdials and positions.

The operatorwill turn the index knob 26 until he obtains a readingl which is within 4the range of the scale and which will thus indicate ythe contents of the tank. However, if this scale readknows that he can double check his reading on a higher or lower dial as indicated. vAssuming that there are 350 gallons `in the tank, but that this capacity is not known by the operator using the system, it will be obvious that if he switches to position l, the pointer will swing off scale on the high side where he is instructed to Read 2. When the operator switches to position2, the pointer will indicate 350 gallons which is the contents of the tank. However, the "350-is indicated on the overlap section and the' operator will know that-'by switching to position 3 he can double check the reading. When the indicator is the pointer will read 350 A'particular advantage of the-overlap system is in the measurement of fuel 'in application such as for aircraft. In this casev flying at variousr `'attitudes usually introduces appreciable errors in the measurement of the fuel. This error can be largely compensated for by the judicious placement of the various transmitters so that as the plane vchanges itsflying attitude, one float in the overlap section will rise while the other will fall; Assuming again the 350 gallon level it will now be found that in position 2 the indicator may read 325 gallons while in position 3 the By averaging these two readings, the correct indication of 350 gallonsis obtained.

While the overlap system will necessarily re- 'sult in a scale that is shorter than when no overlap lsused, it has lthe advantage that the transmitters can be adjusted to read exactly at more vpoints hence increasing the overall accuracy of the system.

vThe parts connected to and moved directly by 'manual adjustments of the index knob 26 are shown in Figs. 2,73, 4, 5, 6 and 7 of the drawings. `The knob 23 is secured to a shaft |0| journaled in the cover |02 of the electrical indicating instrument 20, in mounting plate |03, in a bracket H34 secured to the mounting plate and in two plates 09 and |00 of the switch sections 24 and The plates 09 and |00 are circular and are each provided with a series of holes which may be employed to hold transmitter terminals in any desired number or desired relations.

Attached to the shaft |0I vbetween the bracket |04 and the plate |03 is a spiral gear |0 mesh- "ing with a spiral gear |0| secured to a shaft |08 ,journaled in bosses or extensions which are integral parts of the bracket |04. Secured also to the .shaft |08 is a spur gear |09 (Fig. 3) meshing with a, la'rgergear H0 which turns on a stud vscri-*gw |k set in the side plate ||2 of a yoke |I3.

Rigid with the gear H0 is a, mutilated gear H4,

the spaced apart teeth of which engage between pins' 5 extending from'the right-hand (as seen,

I Rigidly secured to the bracket |04 in any suitable inanner is an arm ||8 (Figs. 2 ande), carry-.-y

asien-se Jing ai: .outer .endareuer il s '.eoopemungwith 1act through theconnections described to yrotate #the dial-carrying `r11- uni 'l l., and vduring this .rotaztiolnthe indexing eamzmemberpLZi will cooperate with the roller filil1to'throw'thedrum back fagainstthe tension .of the springs |22 suiiiciently rer-the dials 4{iL-.22 :and .23 to clear `the indicator pointerild. 'llhermember |21 and roller H9 cooperate `under the iniiuence Vof the springs 122 nto hold the drum AII in any position of adjustment.

. :Secured to the shaft lill between the switch Amounting plates 99 and |60 is amember |25 com- .;posed of. .insulating .material `and ,out away across lits two .radial faces to form seats .for Acontact members |26 composed, at least in part, oi iconducting material to form electrical connections between the common termina-ls v2in1, or 25a and the transmitter `.circuit terminals Amounted lin the holes-in :the 'plates 99 `and |140. By turning the shaft HH .to place .the pointer .20d selectively .under the control-oi the tank floats, thecommon terminals will complete the corresponding transfmitterrfcircuits. The members |26 .are .secured in 'their'.seats .by rivets 1.28ct y.asshowri in Fig. 7.. The various .circuits established by setting the k-nob .26 :are .illustrated diagrammatically in Fig. l :and

the variouscontacts have been indicated in Figs.

vswitch 'contacts .the :member |25 is constructed at an intermediate fpoint togprov-ide a-lobed goor- 'tion oi-member :|21 cooperating with a roller whichxis loos-ely mounted on .a rod supported at titsaends .in the. side plates of .a yoke |29 which is pivoted .on a rodlll :secr-:redet its ends in the -switch mounting plates 99 fand H38. A spring 1.3i :holds the yroller in Contact with the periphery Yofthe member |21, the roller, of course, cooperating with' the recesses `in said member both to insure complete movements ofthe movable switch contacts and .hold them .in Vaccurate alignment with lthe stationary contacts. lie facilitate ad- .giustment .of the movable contacts .and at the .same .time :insu-re satisfactory .engagement with -thestationary contacts, the switch points .I 3.2 and .are yieldingly .mounted as AShown, `for .example, inFig. F1. .fEacl-icontactv .consists ofa cupshaped shell slidable -in va bore in the member 425 with a spring |34 acting Abetween the closed end foi the shell .and 'a conductor .strip |35 to hold the shell in its outermost position. Aflange on the 'shell cooperates with a shoulder on the interior of the bore to limit outward .movement of .the shell. The springs 4M yield, Aof course, as the switch points |32 .ride onto or over :the stationary switch points of the transmitter circuits. yis -seen inthe drawings, `lliligs. 5 to 7, leachcontact :member .|26 is dixedly mounted to the mem 8 her 12:5. `Zlliiscontactmember I 26^provides a cn-i tinudus -zelectrical connection between lthe contacts 132 :and |133., teach oi which isiormed .asa cupfshaped'member `as `shown .in .Fig. 7 4and as .hereinabove described. 'The electrical connection between :thesepointsmay vbe traced through the :springs f|34 fand the conductor strip |35. As the contact .members '|25 are arranged in a nonradialrelation, fasi shown best in Vdotted il-ines in Fig. 56 the radially inner contacts `|33 may 'be arranged to make continuous contact with la member 25a, which in .practicefmay'be formed as :a slip .ring and is seen .lupa-rt in Eig. 7, being ydesignated by the left-hand arrow to reference Vcharacter 25a :in .that figure. The contact |32 positioned onfa-n outer radius vand is arranged .to Ina-ke contact selectively with the several fixed contacts, such as 25h, 25o and 25d, Contact 25d being shown connected 'in Figs. 6 .and 7. genferal, the-electrical arrangement is thus .substantially the same as that shown in Figs. 3 and 6 of De .Giers Patent No. 2,154,066.

No attempt has Ybeen :made to show lthe Iwiring .in-FigS. 2 to 'I of the drawing Aowingto the idili- .cu'lties Joi illustration and because that wiring is diagrammatically illustrated in 4other iigures. However, it can be stated that the wires from the lverrons switch Vcontacts lead to an outlet |36 with Vtheir ends attachedto terminals mounted in the .usual nlug member (not shown) within the outlet. A corresponding plug member vmay vbe insented in theloutlet to (connect the float controlled transmittercircu-its forselective operationiby adjustment of the index knob 2t.

.It will be noted that the dial is constructed 'to provide four dial faces, only three of which have been used in the illustrative embodiments described. The vxmrth dial may be used fior indicating an off condition or it may be employed .for an addi-tional float system where three dials .are insufficient to cover the capacityof the tank.

From .all the foregoing it is believed to be clear that the .dial lchang-ingfmech'anism `jus-t described and the switch contacts are so synchronized that when .a-dial is set in reading relation with the -in- Vilicator pointer 2cd, the transmitter associated with the float Vrepresented by the positioned -dial willylbe connected 'tothe `pointer 28d 1and that thereafter the kposition .oi the float or the level of the iiuid -i-n the tank will be visually indicated Aby .the dial and ypointer until the liquid level passes out of the ,range ci that particular neat; and

vthat l.changes .of the level in Vany lpart ofthe tank may 'be ascertained by turning `the dial Adrum in .eitherdirection to determine which -fioat or floats should befput in control of the pointer to indicate the contents ofthe tank.

lflhat is claimed is.:`

.Apparatus .for .accurately indicating the level -o liquid in a 1tankwh'ich is .of .such shape that the Ientire rangeiof liquid levels A.cannot accurately .besuperyisedfby a single float, comprising a plurali-ty .oct 'floats .mounted .insaid tank at .dierent levelaeachrof `said floats being :sensitiv-,e toa predetermined range -o--l'iqu-id levels, all the ranges together .covering the entire range .oi liquid levels -tolbe indicated land said ranges overlapping l one another by predetemined amounts, -a voltagedividing., potentiometer-type transmitter connectedffto be independently actuated by .each :of saidolurality lof nSli-oats.; a single receiving and .indicating instrument :or `the ratiometer type and includ-ing :a movable .indicator pointer anda plurality Ior ldeiiecien'g coils :arranged to 'be .selerf tively electrically connected :to each .said trans- 9 initter; electrical connections from all said trans mitters to said receiving instrument, selective electric switch means interposed in said electrical connections for connecting said receiving instrument to each of said transmitters, a drum carrying a plurality of scales which are arranged by rotation of said drum to cooperate selectively and optically with said indicator pointer, and a single manually movable element which is mechanically connected to rotate said drum and also to move a movable part oi' said selective electric switch means, so as simultaneously to position a, proper one of said scales in an operative position to cooperate with said indicator pointer when said switch means is moved electrically to connect each of said transmitters with said receiving instrument, whereby said transmitters and oats may be used independently to give an accurate indication of the liquid levels respectively super- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,101,296 Simpson et a1 Dec. 7, 1937 2,103,606 Abrahamsohn et a1. Dec. 28, 1937 2,104,898 De Giers Jan. 11, 1938 2,154,066 De Giers Apr. 11, 1939 2,298,893 MacIntyre Oct. 13, 1942 Certificate of Correction Patent No. 2,516,452

July 25, 1950 CLARENCE A. DE GIERS' ET AL.

It is hereby certied that error appears in the printed specification of the above numbered patent requiring correction as follows:

= Column 5, line 70, for the Words position when read position 1. When; and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the ease in the Patent Ofce.

Signed and sealed this 17th day of October, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant Uommz'ssz'oner of Patents. 

